The best way to identify trees is by the shape of the leaves. Leaves are not all shaped the same, or come in the same size. Some leaves from trees are more pointed, some have several points like a Maple Leaf. This may require research.

The best way to identify different types of trees is by collecting the leaves and sorting them by design. Then look up which leaf belongs to which tree species. After you sort them, you can classify the leaf according to which tree species it belongs to.